Given
[tex]k(x+y)=2x-4[/tex]
Notice that it is the equation of a line.
Then, since it crosses (10,-2), set x=10 and y=-2 in the given equation, as shown below
[tex]\begin{gathered} x=10,y=-2 \\ \Rightarrow k(10-2)=2*10-4 \\ \Rightarrow k(8)=20-4 \\ \Rightarrow k=\frac{16}{8}=2 \\ \Rightarrow k=2 \end{gathered}[/tex]
Thus, the answer is k=2.
